The present invention relates to an electronic barometric sensor unit coupled with a refurbishment module for accurately controlling the detonation of a cutter device for deploying cargo carrying or recovery parachutes as a function of a programmed, barometrically sensed altitude.
Aerial cargo delivery utilizing staged conventional parachute deployment is an established art and has been practiced by the assignee hereof for many years. Historically, the staging or deployment line cutter was actuated by devices which utilized either chemical or electronic time delay means to provide parachute dereefing at an approximate altitude. In other words, the altitude of the aircraft was noted by the operator and a time delay was initiated upon movement of the parachute and cargo from the aircraft which, related to the rate of movement of the parachute and cargo from the aircraft provided a staging of the parachute at an approximate altitude. The time delayed actuation approach requires that the aircraft be at a precisely defined altitude which may be undesirable due to weather conditions, and/or other strategic considerations. Moveover, such delayed actuation approaches are hindered by variables attributable to mechanical and electrical inertia. It is also known in the art to provide dereefing actuators which use mechanical barometric pressure transducers usually of the aneroid capsule type. Aneroid barometric actuation is dependent upon the dropping aircraft altitude and is advantageous when compared with the time delayed reaction stages. Mechanical barometric transducers or switches are not acceptable as an aerial cargo delivery actuation means because of the relatively poor repeatability and the relative high cost since the capsule upon impact with the ground and deceleration forces that it experiences renders it, generally, not useful for further staging operations. Actuation by mechanical barometric means therefore does not appear to offer a net advantage over staging by delayed actuation means described earlier. Essentially all of the prior art staging units have been of the one use--expendible variety.